Alternating-current motor.



V. A. FYNN. ALTERNATING CURRENT MOTOR.

uruoumn FILED JULY 2, 1909.

962,334. Patented June 21, 1910.

5 SHEETS-SHEET 1.

WITNESSES: INVENTOR f, Vjlre A.Fynn

v. A. FYNN. ALTEBNATING CURRENT MOTOR.

APPLICATION FILED JULY 3, 1909.

Patented June 21,1910.

5 SHEETS-SHEET 2.

WIT/(E8858: IN VE N T 0/? V.A.FYNN. ALTERNATING GUBBENT MOTOR.APPLICATION FILED JULY 3, 1909.

Patented June 21, 1910.

5 BKEBTB-BHEET 3.

WITNESSES:

ORNEYS V. A. FYNN.

ALTEBNATING CURRENT MOTOR. APYLIOATIOIYIILED mm a, 1909.

Patented June 21, 1910.

6 SERIES-SHEET 4.

IT rimm n- I mmvms I I Li. W 21 51 V. A. FYNN. ALTERNATING CURRENTMOTOR. APPLIOATIOH nLnn JULY 3, 1909.

Batented June 21, 1910.

' 58KEBT8-8HEET 5.

WITNESSES: INVENTOR ig Vglere AiFynn PATENT OFFICE.

UNITED STATES VALIJBE ALFRED. FYNN, OF LONDON, ENGLAND.

ALTERNATING-CURBENT MOTOR.

To all whom it may concern: I

Be it known that I, VALisnn ALFRED FYNN,

a subject of the King of England, residing at London, En land, haveinvented a certain new and usefu Alternating-Current Motor,

of which the following is such a full, clear, and exact description aswill enable any one skilled in the art to which it appertains to makeand use the same, reference being had to the accompanying drawings,forming part of this specification.

' My invention relates to means for starting and operating single phaseinduction motors in which the in need winding responsible for theoperation of the motor is permanently closed on itself independently ofany commutator. It is known that motors of this type have distinctmechanical advantages and good operating characteristics but aredifficult to start with a powerful torque and with a small current or inother words with a large torque per ampere.

One object of my mventionis to provide such means for startingsaidmotors. with a large torque per ampere as will not make it necessary todimension or dispose the secondary working winding permanently closed onitself with any other objects in View but those of highest effectivenessand eiiiciency under normal running conditions.

Other objects of my invention are to avoid the use of all automaticshort-circuiting devices inside the rotor, to provide means forcompensating such machines and to generally improve their characteristicroperties both at starting and under norma working conditiona I achieveiny objects by providing my motor with a rotor having a permanentlyshort-circuited winding extending over all the rotor laminations and apluralit of commuted. windings longitudinally isplaced and extendingover a part only of the rotor laminations, by conveying a workingcurrent to each commuted winding and neutralizing the effects of suchcurrents on the shortcircuited winding, by producing a motor fluxthreading each commuted winding and adapted to produce a starting torquewith the ampere turns due to the correspondin workin current whileneutralizing the e fects 0 said motor fluxes on the short-circuitedwinding and by inducing currents in Specification of Letters Patent. P tt d J n 21, 1910, Application filed July a, 1909; Serial No. 505,779.

the short-circuited winding either at the moment of starting or afterthe motor has reached a sufficient speed, thus limiting the speed of themachine and converting same into a self-excited shunt induction motor.and finally by impressing on at least one of the commuted windings,preferably after the motor has reached a sufficient speed, an E. M. F.of suitable phase for improving the power factor 2'. e. compensating themotor. Thus in my preferred form of motor I provide a permanently shortcircuited working winding on the induced or secondary member togetherwith two commuted windings on that member and so Wind the inducing orprimary member that in one connection or combination of its windin s thesecondary working winding permanent y closed on itself will not carryany currents, whereas in another connection or combination of thewindings on the inducing member the secondary working windingpermanently closed on itself will have currents induced in it which willclose in that winding without the help of a commutator. firstconnections are used at starting, the second are used in normaloperation. I further so connect or combine the windings disposed on theprimary member that the motor may start as a series induction, as aseries or a shunt conduction motor. In normal operation one or more ofthe commuted windings may in some modifications, also carry workingcurrents thus contributing to 'the useful torque.

In all induction motors there is a trans former flux which conveysenergy from the inducing to the induced member, and a motor fiux whichproduces torque with the current induced in the secondary. In conductionmotors there is sometimes a fluxdue to the working current in thearmature and there is always a motor flux. I preferably dispose mywindings in such a manner that neither of these fluxes will produce anycurrents in the permanently short-circuited secondary working winding atstarting and before the primary connections have been altered from thestarting to the running connections. I may make the necessary change inthe connections automatically or by hand. If an automatic, for instancea centrifugal,

device is used it can be placed outside the The motor; it can thereforealways be made easily accessible, can be kept in good con: dition andcan be quickly repaired 'or replaced. When the machine has reached asufiicient speed I can make use of one or more of the commuted windingsfor the purpose of compensating, i. 6'. improving-the power factor ofthe machine. By suitably interconnecting the commuted windings I cancause a working current to flow through these windings independently ofthe commutator, thus relieving the latter and obviating all danger ofsparking.

In describing some ways of carrying my invention into practice I willrefer to the accompanying diagrammatic drawings of two-pole motorswherev Figure 1 shows a motor in which the two commuted windings areinterconnected, which is capable of being compensated and is arranged tostart as a separately excited series induction machine with the motorfield winding disposed on'the inducing member. Fig. 2 indicates themechanical disposition of the motor parts for the machine shown inFig. 1. Fig. 3 is a motor capable of being compensated and arranged tostart as a separately excited series induction motor with the'motorfield winding disposed on the induced'member. F ig. 4 is a motor capableof being compensated by means of a transformer independent of the motorand arranged to start as a self-excited series induction motor inwhich'the motor field winding is disposed on the induced member. Fig. 5is a motor capable of being compensated and arranged to start mainly asa neutralized series conduction motor. Fig. 6 is a motor capable ofbeing compensated and arranged to start as a shuntconduction motor.

Fig. 1 shows a motor with two longitudinally displaced primary or statorwindings 7 and 8 disposed along parallel axes,. ar-

- ranged to be connected in parallel and to be fed from the mains 1, 2by way of a transformer having a primary 3 and a secondary 4. Themovable contact 5'on the latter controls the magnitude of the. E. M. F.impressed on the circuit containing 7, whereas 6 controls the magnitudeof the E. M. F. impressed on the circuit containing 8. An automaticswitch '9, here shown as being of the centrifugal type, is adapted to begeared to the motor shaft for instance by means of the pulley 10.-When'the motor isat rest the contact levers 11 and 12 of.9, which areinsulated from the body of 9, are in the position shown; after the motorhas reached a sufiicient speed these levers leavecontacts 15, 20 and 17,14 and bridge the contacts 13, 19 and 18, 16. It is best to so design 9.as to cause these levers to snap from the starting to the runningposition. The secplaced and similarly interconnected com muted windings34, 35. The first is shortcircuited by means of the brushes 36, 37

' along an axis approximately coinciding with that of 7, the second isshort-circuited by the brushes 40, 41 along an axis approximatelycoinciding with that of 8.

Each commuted winding carries exciting brushes 38, 39 and 42, 43; theseexciting brushes are displaced by about 180/n degrees with respect tothe correspondin shortcircuited brushes or with respect to t e axes of 7and 8 respectively. The letter 1:. stands throughout for the number'ofpoles of the motor. The exciting brushes 38, 39 can be connected to thecompensating winding 54 by means of the reversing switch 76. The

exciting brushes 42, 43 can be connected to the compensating winding 55by means of 77. The direction of the com ensating E. M. F. iscontrolledby 76, 77, t ese switches being closed in the one or the otherdirection according to the direction of rotation and after the motor hasreached a suflicient speed. Switch 74 controls the direction of thecurrent through the'motor field windings 66, 67 dis osed on the inducingmember. This switch, therefore, controls the direction of rotation ofthe motor. Switch 71 is adapted to cut the stator field windings 66, 67out of circuit. At starting all switches are in the positions shown.WVith reference to the shortcircuited winding 24, 25, the inducingwinding 8 magnetizes in a direction opposite to that of themagnetization due to 7 and the movable contacts 5 and 6, if such areused, are preferably so adjusted that the E. M. F.s induced in 24 and 34are of equal magnitude to those induced in 25 and 35 respectively. Atstarting the primary circuit is as follows: from point 52 of 4 to switch74 through 66, 67 in one or the other direction, out through 71 and 74to point 51 from there through 7 and 5 back to 4 and also from 51through 17, l1, 14 to 8 and through 15, 12, 20 and 6 back to 4.

Since the magnetizations due to 7 and 8 are of op osite'direction withrespect to 24,

magnitude then no current will flow by way of the interconnectionsbetween 24 and 25, i, 6. there will be no current from 28 to 29, 26 to27, 56 to 57 and so; on. The effect of the transformer fluxesiion theshort-circuited working winding thus eliminated.

The E. M. F s induced in the commuted windings 34, 35 will, however,determine a local current in each of them. These local currents willclose by way of the short-circuited brushes 36, 37 and 40, 41respectively.

The current in 34 will be of opposite direction to that in 35 and inorder that-these two windin shall give torques in the same direction t eprimary current conducted through 66 for the purpose of generating amotor field adapted to interact with the current induced in 34 must beconducted through 67 in a direction opposed to that in which it isconducted through 66. This is clearly shown in Fig. 1. This motor startsas a separately excited series induction motor, the longitudinallydisplaced stator windings 66, 67 doing duty as motor field windings.Since the fluxes due to 66 and 67 are of opposite direction with respectto 24, 25 their efiect on the short-circuited working winding 24, 25will be nil provided the magnitude of these fluxes is approximately thesame, nor will these fluxes cause any currents to flow in theconnections between 34 and 35. Since these fluxes are due to the samecurrent it is only necessary that the number of turns in 66, 67 and therelative space position of 66 to 24, 34 and of 67 to 25, 35 as well asthe relative brush positions be sensibly the same in order that thisdesired condition may be practically fulfilled. It is seen that theshort-circuited working winding 24, 25 is quite idle at startmg.

As the motor gathers speed the E. M. F.

impressed on 8 may, if desired, be gradually diminished down to .Zero,when .8 will be short-circuited. After that the E. F. impressed on 8 maybe gradually increased in the opposite direction. In most cases it willbe quite suflicient to simply reverse the current through 8 after themotor has reached a sufliciently high speed. In Fig. 1' this is achievedby means of the automatic switch 9. As soon as 8 has been reversed thenthe combined windings 24, 25 and 34, 35 act just like the ordinaryshort-circuited secondaries of a self-excited single-phase shuntinduction motor of ordinary construction, both these combined windingsbecoming working windings. The brushes could.

now all be lifted oil the commutators but I prefer to leave all thebrushes on the commutato'r and to close the circuit of the excitingbrushes so as'to include a com ensating E. M. F. in the excitingcircuits 0 either 34' or 35 or of both, thus making use of 34,

35 for compensating purposes as well as for carrying part of the loadcurrent. This compensation is achieved in Fig. 1 by closingswitches 76and 77 in the proper direction. It is preferred, after the motor hasreached a sufiiciently high speed, to cut' 66 and 67 out of circuit bymeans of 71. The windings 7 and 8 are shown connected in parallel but itis obvious that they can also be connected in series and if it were notfor the fact that the current through one of them must in this case becapable of being reversed they could be replaced by a single winding. Amodified construction embodying this idea is shown in Fig. 6.

In order to provide for an easy accommodation of the longitudinallydisplaced stator and rotor windings the motor laminations can be splitup into two groups in the manner indicated in Fig. 2. The two groups ofstator laminations are shown at 44 and 45; the two longitudinallydisplaced stator windings at 7 and 8; the two compensating windings at54, 55; the field windings at 66, 67. The two groups of rotorlaminations are shown at 46, 47. They are mounted on the same shaft andare spaced to correspond to 44 and 45. The two longitudinally displacedcommuted windings are shown at 34, 35; their respective commutators at48, 49 and their interconnections are indicated at 75. In Fig. l theworking winding 24, 25 permanently closed on itself independently of acommutor has een;

connected windings are electrically equivalent to a single winding, forinstance to a squirrel cage such as shown in Fig. 2 and wound straightthrough both groups of the rotor laminations. This squirrel cage hasbeen designated by the two numerals 24, 25 in Fig. 2 so as to drawattention to the fact that it is the equivalent of the twointerconnected windings 21, 25'of Fig. 1. In

practice it will generally be more advantageous to make use of asquirrel cage construction for the working winding permanently closed onitself. It is immaterial whether the two groups of laminations 44, 45are inclosed within the same or within separate frames. It is, however,necessary that the two groups of rotor laminations be rigidly coupledand that the part\of the short circuited working winding disposed on onegroup of rotor laminations be electrically connected at a plurality ofpoints to that part of this same winding which is disposed on the otherroup of rotor laminations. The stator windings 7, 8 need'not be disposedalong parallel axes. The windings disposed on 44, 46 have been shown inFigs. 1 and 2 as 2 pole windings, those disposed on 45, 46 have alsobeen shown as 2 pole windings, but this is by no means neces saryalthough it is the preferred arrangement. The number of poles of thewindings disposed on one group of stator and rotor laminations maydiffer to any desired extent from that of the windings disposed onanother group of such laminations.

In Fig. 3 the two longitudinally displaced stator windings 7, 8 aredirectly connected to the mains l, 2, the reversing switch 53 is arraned to control the direction of the current t rough 8. The inducingwindings 7 and 8 magnetize in opposite directions at starting but thecurrent through 8 is reversed after the motor has reached a suffi-.cient speed. Accordingly the rotor working winding permanently closedon itself is so arranged that the E. M. F.s induced therein oppose eachother when 7 and 8 magnetize in opposite directions and are in the samedirection when 7 and 8 magnetize in the same direction. This isdiagrammatically indicated in Fig. 3 by connecting point 28 to 29, point26 to 27, point 32 to 33 and point 30 to 31. The motor field is producedby connecting the commuted windin s 34, 35 in series relation with theinducing stator windings. This is achieved in Fig. 3 by connecting point51 to brush 38, brush 39 to brush 43 and brush 42 to the main 2. Theline current is thus taken through the rotor along an axis displaced byabout 180/n degrees with resepct to the axes of 7 and 8. Since thecurrent induced in 34 at starting is of opposite direction to thatinduced in 35 then the exciting current must be taken in oppositedirections through34 and 35 in order to secure torques in the samedirection. The commuted windings 34, 35 are not interconnected in thiscase, but they are nevertheless active at starting and in normaloperation. All the currents flowing in these windings now close by wayof the commutator only even in normal operation. When .34, 35 are notinterconnected then a common source of compensating E. M. F. can be madeuse of. In this case the exciting brushes on both windings are connectedto part 23 of winding 7 when switches 21 and 22 are closed and this part23 of 7 then acts as compensating windin Switches 21, 22 are preferablyclosed a r the motor has reached a sufficient speed and the currentthrough 8 has been reversed.

In Fig. 4 the windings 7, 8 are arranged to magnetize in the samedirection at starting. The commuted windings 34, 35 are notinterconnected although they can be interconnected if desired. Theinterconnections of 24, 25 are also altered. Thus point 28 is connectedto point 33 instead of 29 and so on. If 34 and 35 are to beinterconnected then point 56 should be connected to 61 and so on. Thestarting is accomplished by displacing the short-circuited brushes 36,37 from the axis of 7 and the short-circuited brushes 40, 41 from theaxis of 8. Since the torques due to 34 and 35 are to add thesedisplacements should be in the same direction, irrespective of therelative direction of the magnetization due to 7 and 8 respectively, andthe degree of displacement should be such in each case that the motorfield due to 35 equals the motor field due to 34, thus eliminating theaction of those motor fields on the short-circuited working winding 24,25 at starting. After the motor has reached a suflicient speed thecurrent through 8 is reversed and if phase compensation is desired thenswitches 21, 22 are closed thus impressing compensating E. M. F.s on theexciting brushes 38, 39 and 42, 43. These E. M. F.s are here derivedfrom a shunt transformer, the primary 68 of which is connected acrossthe mains 1, 2. This transformer has two independent and regulatablesecondaries 78, 79. If 34, 35 are not interconnected then one secondaryis sullicient. The short circuited brushes may be moved so as tocoincide with the axes of 7 and 8 after the motor is up to speed. Thedirection of rotation can be reversed by moving the shortcircuitedbrushes beyond the axes of 7 and 8. If the short circuited workingwinding 24, 25 were for instance of the squirrel cage type then one andthe same bar would have to pass the two groups of rotor laminationsthrough slots displaced by about 360/71, degrees in order to correspondto the interconnections between 24 and 25 which are shown in Fig. 4. 4

The motor shown in Fig. 5 carries two inducing windings 7 and 8connected in parallel. The two parts 24 and 25 of the shortcircuitedworking winding are sointercohnected that this winding will beresponsive to induction effects due to 7 and 8. In practice a squirrelcage such as shown in Fig. 2 would be used instead of the interconnectedwindings 24, 25. The actual starting circuit consists of theneutralizing windings 99, 98, the commuted windings 34, 35 and the motorfield windings 66, 67. All the elements of this starting circuit areconnected in series, the commuted windings being included by way of thebrushes 36, 37 and 40, 41 respectively. At starting switch 74 stands onpoints 101, 103 and switch 100 can be left open. The machine starts as aneutralized series conduction motor and the torque and speed may bevaried by adjusting the movable contact 6 on the secondary 4 of thetransformer with the primary 3 feeding the motor from mains 1,2. when asuflicient s eed has been reached switch 100 is close thus bringing theshort-circuited rotor working winding into play and converting themachine into a self-excited i-shunt induction motor. The startingcircuit may now simply be opened thus rendering the commuted windingsidle or these maybe made use of to compensate the machine. One way ofachieving this is shown in Fig. 5 and consists in moving 74 on to points102 and .104. The motor field windings 66, 67 now act as compensatingwindings, the compensating E. M. F.s being induced therein by 7 and 8.The whole or part only of the motor field windings may be used forcompensating purposes. Since the currents flowing through 34- and 35 atstarting flow in relatively op osite directions than the fluxes theywould set up will not induce currents in 24, 25 and the neutralizingwindings 99, 98 can be omitted if desired. Switch 100 can be closed atstarting and although this will reduce the torque per ampere yet thefluxes due to 7 and 8 will not otherwise interfere with the startingoperation and will prevent the motor from racing. The two windings 7 and8 can of course be replaced by a single one embracing both groups ofstator-laminations.

In Fig. 6 the stator carries three windings. One of these embraces bothgroups of stator laminations and is shown at 97. It takes the place ofthe two windings 7 and 8 of Fig. 5 whether the latter be connected inseries or in parallel. Thewindi'ngs 24, 25 are so interconnected as to,form a shortcircuited winding responsive to inductive effects due to97. The stator windings 117 and 118 are adapted to produce fluxes whichlink with 34 and 35 respectively and are conductively connected. tothese commuted windings by way of the brushes 36, 37 and 40, 41respectively. At starting switch 119 stands .on points 115, 116 thusconnecting 117 and 118 in parallel and to the supply. The motor startsas a shunt conduction machine owing to the interaction of the fluxes dueto 117 and 118 threading 34 and 35 and the ampere turns in 34 and 35 dueto the currents derived from 117 and 118 and'conducted through 34 and 35respectively by way of the brushes. The starting torque can be regulatedat 120 and 121. When a sutficient speed has been reached switch 119 isthrown on to point 114 whereby 117, 118 are disconnected from the supplyand 97 is connected to the mains 1, 2. The short-circuited workingwindings 24, 25 now comes into play. The flux due to 97 also induces E.M. F.s in 117 and 118. These E.M.F,'s are made use of for compensatingthe machine and no further change of connections is required to achievethis purpose for the commuted windings are already connected.

to 117 and 118 byway of the brushes 36, 37 and 40, 41. The magnitude ofthe compensating E. M. F .s can be adjusted at 120 and 121. If 97 isconnected to the supply at starting then the motor will never exceed itsnormal speed but the torque per ampere at starting will be somewhatreduced particularly if the full line voltage is impressed on 97 fromthe very first.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In an alternating current motor, the combination with a stator, of alaminated rotor provided with a permanently shortcircuited winding andtwo commuted windings, said short-circuited winding extending over allthe rotor lamirations and each.

winding and two commuted windings, said short-circuited windingextending over all the rotor laminations and each of said commutedwindings extending over a part only of the rotor laminations.

. 3. In an alternating current motor, the combination with a statorprovided with a plurality of windings, of a rotor containing twolongitudinally displaced groups of laminations and provided with apermanent-1y short-circuited winding and two connnuted windings, saidshort-circuited winding extending over both groups of rotor laminationsand each of said commuted windings extending over only one group ofrotor laminations.

4.- In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, means for producing amain flux through each group of laminations, a laminated rotor providedwith a permanently short-circuited winding and two commuted-windings,said short-circuited winding extending over all the rotor laminationsand each of said commuted windings extending over a part only of therotor laminations.

5. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, each group beingprovided with a main winding, a laminated rotor provided with apermanently short-circuited winding and two commuted windings, saidshort-circuited winding extending over all the rotor laminations andeach of said commuted windings extending over a part only of the rotorlaminations.

6. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, means 'for Cit producinga main flux through each group of laminations, two auxiliary windings,one of which is coaxially disposed with reference to the main fluxthrough one group of laminations, a laminated rotor provided with apermanently short-circuited winding and two commuted windings, saidshortcircuited winding extending over all the rotor laminations and eachof said commuted windings extending over a part only of the rotorlaminations. I

'7. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, means for producing amain flux through each group of laminations, an auxiliary windingcoaxially disposed with reference to themain flux through one group oflaminations, a laminated rotor provided with a permanentlysho'rt-circuited winding and two commuted windings, said short-circuitedwinding extending over all the rotor laminations and each of saidcommuted windings ex tending over a part only of the rotor laminations.

-8. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, means for producing amain flux through each group of laminations, two auxiliary windings, oneof which is coaxially disposed with reference to the main flux throughone group of laminations, a laminated rotor provided with a permanentlyshort-circuited. winding and two commuted windings, said shortcircuitedwinding extending over all'the rotor laminations and each of saidcommuted windings extending over a part only of the rotor laminations,and separate means for directing the flow of current inv each of thecommuted windings.

9. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, means for producing amain flux through each group of laminations, an auxiliary windingcoaxially disposed with reference to the main flux through one group oflaminations, a laminated rotor provided with a permanentlyshort-circuited winding and two commuted windings, said short-circuitedwinding extending over all the rotor laminations and each of saidcommuted windings extending over a part only of the rotorlaminations,.and separate means for directing the How of current in eachof the commuted windings,

10. In an alternating current motor, a stator' containing twolongitudinally displaced groups of laminations, means for producing amain flux through each group of laminations, a laminated rotor providedwith a permanently short-circuited winding and two commuted windings,said short-circuited winding extending over all the rotor laminationsand each of said commuted windings extending over a part only of therotor laminations, and separate means for directing the flow of currentin each of the commuted windings.

11. In an alternating current motor, the combination with a laminatedrotor vided with a permanently short-circulted winding and two commutedwindings, said short-circuited winding extending over all the rotorlaminations and each of said commuted windings extending over a partonly of the rotor laminations, of two stator windings longitudinallydisplaced from each other and adapted to produce magnetic fluxes throughthe rotor, said magnetic fluxes being of such position and direction atstarting that the permanently short-cin cuited winding will beinoperative.

12. In an alternating current motor, a rotor containing twolongitudinally displaced groups of laminations and provided with apermanently short-circuited winding extending over both of said groupsand two commuted windings each extending over only one of said groups,and means for producing a transformer flux through each group of rotorlaminations and means for producing a motor flux through each group ofrotor laminationsat starting.

13. In an alternating current motor, a rotor containing twolongitudinally displaced groups of laminations and provided with apermanently short-circuited winding extending over both of said groupsand two commuted windings each extending over only one of said groups,said commuted windings being interconnected at a plurality of points,and means for producing a transformer flux through each grou) of rotorlaminations and means for pro ucing a motor flux through each group ofrotor laminations at starting.

14. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, means for producing amain flux through each group of laminations, a rotor containing twolon-,

gitudinally displaced groups of laminations and provided with apermanently short-circuited winding and two.commuted windings, saidshort-circuited winding extending over both groups of laminations andeach of said commuted windings extending over only one' group oflaminations.

15. In an alternating current motor a stator containing twolongitudinally placed groups of laminations, means forproducing a mainflux through each group of laminations, two auxiliary windings, one ofwhich is coaxially disposed with reference to the main flux through onegroup of laminations, a rotor containing two longitudinally displacedgroups of laminations and provided with a permanently short-circuited\vindin and two commuted windings, said short-circuited windingextending over both groups of laminations and each of said commutedwindings extending over only one group of laminations.

16. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, means for producing amain flux through each group of laminations, an auxiliaryv windingcoaxially disposed with reference to the main flux through one group oflaminations, a rotor containing two longitudinally displaced groups oflaminations, and rovided with a permanently sliort-circuite winding andtwo commuted windings, said short-circuited winding extending over bothgroups of laminations and each of said commuted windings extending overonly one group of laminations.

17. In an alternating current" motor, a stator containing twolongitudinally dis placed groups of laminations, eachgroup beingprovided with a main winding, a rotor containing two longitudinallydisplaced groups of laminations and provided with a permanentlyshort-circuited winding and two commuted windings, said short-circuitedwinding extending over both groups of laminations and each of saidcommuted windings extending over one group of'laminations, and brushesfor .conductively conveying a current to each commuted winding along anaxis displaced from the axis of the corresponding main stator winding.

18. In an alternating current motor, a stator containing twolongitudinally displaced groups of laminations, each group beingprovided with a main winding, two

auxiliary windings, one of which is coaxially disposed with reference toone of said main windings, a rotor containin two longitudinallydisplaced groups of aminations and provided with a permanentlyshortcircuited windin and two commuted windings, said short-circuitedwinding extendin over both grou s of laminations and each 0 said commutewindings extending over only one grou of laminations, and brushes forconductive y conveying a current to each commuted winding along an axisdisplaced from the axis of the corresponding main stator winding. v

19. In an alternating current motor, a stator containin twolongitudinally displaced grou s 0% laminations, each group being provied with a main winding and two auxiliary windings, one ofrwhich iscoaxially disposed with reference to said main winding, a rotorcontainin two longitudinally displaced groups of aminations and providedwith a permanently short-circuited winding and two commuted windings,said short-circuited winding extending over both groups of laminationsand each of said commuted windin extending over only one group oflaminations, brushes for conductively conveying a current to eachcommuted winding along an axis displaced by approximately 180/n degreesfrom the axis of the correspondin brushes for s ort-circuiting eachcommuted winding along another axis.

20., In an alternating current motor, a stator containing twolongitudinally displaced ,groups of laminations, each group beingprovided with a main winding, a rotor containin two longitudinallydisplaced groups 0 laminations and provided with apermanently.short-circuited winding extending over both groups oflaminations and each of said commuted windings extending over only onegroup of laminations, brushes for conductively conveying a current toeach commuted winding along an axis dis placed by approximately 180/71,degrees from the axis of the corresponding stator winding, and brushesfor short-circuiting each commuted winding along another axis.

21. In an alternating current motor a stator containing twolongitudinally isplaced groups of laminations, each group being providedwith a main winding, a rotor containing two longitudinally displacedgroups of laminations and provided with a a permanently short-circuitedwinding and two commuted windings, said short-circuited windingextending over both groups of laminations and each of said commutedwindings extending over only one group of lami-i nations, and means forreversing the current through one of the main stator windings.

22. In an alternating current motor, a stator containin twolongitudinally displaced groups 0 laminations, each group being providedwith a main winding and two auxiliary windings, one of which iscoaxially disposed with reference to said main winding, a rotorcontaining two longitudinally spaced groups of laminations and providedwith a permanently short-circu1ted main stator winding, and

winding and two commuted windings, said short-circuitedwinding extendingover both groups of laminations, brushes for conductively conveying acurrent to each commuted winding along an axis displaced byapproximately ISO/n degrees from the axis of the a corresponding mainstator winding, brushes for short-circuiting each commuted winding alonganother axis, and automatic means for reversing the current through oneof the main stator wmdin 23. In an a l ternating current motor, thecombination with a stator, of a laminated .rotor. provided with apermanently shortcircuited winding and two commuted windings, saidshort-circuited winding extending over all the rotor laminations andeach of said commuted windings extending over a art only of the rotorlaminations and means or impressin a compensating E. M. F. on at leastone o the commuted windings.

24. In an alternating current motor, a rotor containin twolongitudinally displaced groups 0 laminations and provided with apermanentl short-circuited winding extending over bot of said groups andtwo commuted windings each extending over only one of said groups, meansfor producving a transformer flux through each group of rotorlaminations and means for producing a motor flux'through each group ofrotor laminations at starting, and .means for impressing a compensatingE. M. F. on at least one ofthe commuted windings.

In testimony whereof I have hereunto set my hand and affixed my seal inthe presence of the two subscribing witnesses.

VALERE ALFRED FYN N. [1. s.]

Witnesses:

ELIZABETH BAILEY, E. E. HUFFMAN.

